1. Field of the Invention
The present technology relates to a semiconductor device to be used as a switching element of a power supply circuit, and more particularly to a technique for effectively improving power conversion efficiency, and miniaturization.
2. Description of the Related Art
In recent years, a power conversion device represented by a high-power supply circuit has been expected to reduce a power loss and improve power conversion efficiency. In particular, a DC-DC converter which is used in a power supply circuit in a personal computer or a stationary game machine tends to output a large current to drive a central processing unit at high speed. Therefore, it is a great issue to improve the power conversion efficiency.
The DC-DC converter is comprised of a high-side switch and a low-side switch, and each switch is made of a power semiconductor. Thus, the power conversion is performed by alternately turning ON/OFF the high-side switch and the low-side switch in synchronization with each other. The high-side switch is a control switch, and the low-side switch is a synchronous rectifying switch in the DC-DC converter.
In a case where each of the high-side switch and the low-side switch is comprised of one package, a parasitic inductance is generated due to wire bonding of the semiconductor device, or a wiring of the package to be mounted on a printed substrate. In particular, when a main current flows through the parasitic inductance on a side of a source terminal of the high-side switch, induced electromotive force is generated. Thus, the turn-on of the high-side switch is delayed, which causes power conversion efficiency to be lowered.
Thus, as one technique to improve the power conversion efficiency of the DC-DC converter, Patent Literature 1 discloses a technique to reduce an influence of the parasitic inductance due to the wire bonding or the wiring of the package.
Patent Literature 1 discloses the technique to improve the power conversion efficiency of the DC-DC converter by integrating the high-side switch and the low-side switch into one chip. More specifically, the high-side switch and the low-side switch are not provided as discrete components, but integrated into the one chip to eliminate a wire for connecting the switch and a wiring on a mounting substrate. Furthermore, the integration into the one chip can considerably reduce a module size.